scholarly journals Fabrication and Packaging of CMUT Using Low Temperature Co-Fired Ceramic

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 553 ◽  
Author(s):  
Fikret Yildiz ◽  
Tadao Matsunaga ◽  
Yoichi Haga
Keyword(s):  
Low Temperature ◽  
Integrated Circuit ◽  
Flip Chip ◽  
Ultrasonic Transducer ◽  
Silicon On Insulator ◽  
Anodic Bonding ◽  
Lateral Side ◽  
Membrane Thickness ◽  
Bonding Performance ◽  
Complex Admittance

This paper presents fabrication and packaging of a capacitive micromachined ultrasonic transducer (CMUT) using anodically bondable low temperature co-fired ceramic (LTCC). Anodic bonding of LTCC with Au vias-silicon on insulator (SOI) has been used to fabricate CMUTs with different membrane radii, 24 µm, 25 µm, 36 µm, 40 µm and 60 µm. Bottom electrodes were directly patterned on remained vias after wet etching of LTCC vias. CMUT cavities and Au bumps were micromachined on the Si part of the SOI wafer. This high conductive Si was also used as top electrode. Electrical connections between the top and bottom of the CMUT were achieved by Au-Au bonding of wet etched LTCC vias and bumps during anodic bonding. Three key parameters, infrared images, complex admittance plots, and static membrane displacement, were used to evaluate bonding success. CMUTs with a membrane thickness of 2.6 µm were fabricated for experimental analyses. A novel CMUT-IC packaging process has been described following the fabrication process. This process enables indirect packaging of the CMUT and integrated circuit (IC) using a lateral side via of LTCC. Lateral side vias were obtained by micromachining of fabricated CMUTs and used to drive CMUTs elements. Connection electrodes are patterned on LTCC side via and a catheter was assembled at the backside of the CMUT. The IC was mounted on the bonding pad on the catheter by a flip-chip bonding process. Bonding performance was evaluated by measurement of bond resistance between pads on the IC and catheter. This study demonstrates that the LTCC and LTCC side vias scheme can be a potential approach for high density CMUT array fabrication and indirect integration of CMUT-IC for miniature size packaging, which eliminates problems related with direct integration.

Finite Element Modelling of Air-Coupled Circular Capacitive Micromachined Ultrasonic Transducer for Anodic Bonding Process using SOI Wafer

2021 ◽  
Author(s):  
Gurpreet Singh Gill ◽  
Sanjay Kumar ◽  
Ravindra Mukhiya ◽  
Vinod Kumar Khanna
Keyword(s):  
Finite Element ◽  
Resonance Frequency ◽  
Glass Substrate ◽  
Ultrasonic Transducer ◽  
Fem Simulation ◽  
Silicon On Insulator ◽  
Anodic Bonding ◽  
Free Standing ◽  
Design Flexibility ◽  
Capacitive Micromachined Ultrasonic Transducer

Abstract Capacitive Micromachined Ultrasonic Transducer (CMUT) provides an alternative to commercial piezoelectric-based ultrasonic transducers due to its wide bandwidth, improved efficiency, sensitivity, and design flexibility [1, 2]. In this paper, Finite Element Method-based design and simulations of circular capacitive micromachined ultrasonic transducer (CMUT) is presented. The FEM simulation of air-coupled CMUT was accomplished by using MEMCAD tools CoventorWare® and COMSOL™. The resonance frequency of 3.9 MHz was achieved for the designed circular CMUT device. A favourable agreement was found for the resonance frequency and pull-in voltage of the device using MEMSCAD tools and analytical calculations. For the proposed CMUT design, a circular cavity will be formed inside the glass substrate. Then, a free-standing membrane will be released using active layer of silicon-on-insulator (SOI) wafer. The bulk silicon of SOI wafer will be removed after bonding it on the glass substrate using anodic bonding technique as described in fabrication process flow for CMUT.

scholarly journals Low temperature co-fired ceramic packaging of CMOS capacitive sensor chip towards cell viability monitoring

2016 ◽  
Vol 7 ◽  
pp. 1871-1877 ◽  
Author(s):  
Niina Halonen ◽  
Joni Kilpijärvi ◽  
Maciej Sobocinski ◽  
Timir Datta-Chaudhuri ◽  
Antti Hassinen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cell Viability ◽  
Integrated Circuit ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Capacitive Sensor ◽  
Circuit Board ◽  
Sensor Chip ◽  
Microfluidic Channels ◽  
Label Free

Cell viability monitoring is an important part of biosafety evaluation for the detection of toxic effects on cells caused by nanomaterials, preferably by label-free, noninvasive, fast, and cost effective methods. These requirements can be met by monitoring cell viability with a capacitance-sensing integrated circuit (IC) microchip. The capacitance provides a measurement of the surface attachment of adherent cells as an indication of their health status. However, the moist, warm, and corrosive biological environment requires reliable packaging of the sensor chip. In this work, a second generation of low temperature co-fired ceramic (LTCC) technology was combined with flip-chip bonding to provide a durable package compatible with cell culture. The LTCC-packaged sensor chip was integrated with a printed circuit board, data acquisition device, and measurement-controlling software. The packaged sensor chip functioned well in the presence of cell medium and cells, with output voltages depending on the medium above the capacitors. Moreover, the manufacturing of microfluidic channels in the LTCC package was demonstrated.

scholarly journals A Resonant Pressure Microsensor with a Wide Pressure Measurement Range

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 382
Author(s):  
Chao Xiang ◽  
Yulan Lu ◽  
Chao Cheng ◽  
Junbo Wang ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Chemical Mechanical Planarization ◽  
Measurement Range ◽  
Silicon On Insulator ◽  
Anodic Bonding ◽  
Pressure Measurements ◽  
Quality Factors ◽  
Deep Reactive Ion Etching ◽  
Wide Range ◽  
Form Pressure ◽  
Silicon Islands

This paper presents a resonant pressure microsensor with a wide range of pressure measurements. The developed microsensor is mainly composed of a silicon-on-insulator (SOI) wafer to form pressure-sensing elements, and a silicon-on-glass (SOG) cap to form vacuum encapsulation. To realize a wide range of pressure measurements, silicon islands were deployed on the device layer of the SOI wafer to enhance equivalent stiffness and structural stability of the pressure-sensitive diaphragm. Moreover, a cylindrical vacuum cavity was deployed on the SOG cap with the purpose to decrease the stresses generated during the silicon-to-glass contact during pressure measurements. The fabrication processes mainly contained photolithography, deep reactive ion etching (DRIE), chemical mechanical planarization (CMP) and anodic bonding. According to the characterization experiments, the quality factors of the resonators were higher than 15,000 with pressure sensitivities of 0.51 Hz/kPa (resonator I), −1.75 Hz/kPa (resonator II) and temperature coefficients of frequency of 1.92 Hz/°C (resonator I), 1.98 Hz/°C (resonator II). Following temperature compensation, the fitting error of the microsensor was within the range of 0.006% FS and the measurement accuracy was as high as 0.017% FS in the pressure range of 200 ~ 7000 kPa and the temperature range of −40 °C to 80 °C.

scholarly journals Effect of rare earth oxide CeO2 on the anodic bonding performance of PEG-based MEMS encapsulation materials

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110077
Author(s):  
Chao Du ◽  
Cuirong Liu ◽  
Xu Yin ◽  
Haocheng Zhao
Keyword(s):  
Tensile Strength ◽  
Rare Earth ◽  
Rare Earth Oxide ◽  
Solid Polymer Electrolytes ◽  
Anodic Bonding ◽  
Solid Polymer ◽  
Bonding Layer ◽  
Scanning Calorimetry ◽  
Ion Migration ◽  
Bonding Performance

Herein, we synthesized a new polyethylene glycol (PEG)-based solid polymer electrolyte containing a rare earth oxide, CeO2, using mechanical metallurgy to prepare an encapsulation bonding material for MEMS. The effects of CeO2 content (0–15 wt.%) on the anodic bonding properties of the composites were investigated. Samples were analyzed and characterized by alternating current impedance spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, tensile strength tests, and anodic bonding experiments. CeO2 reduced the crystallinity of the material, promoted ion migration, increased the conductivity, increased the peak current of the bonding process, and increased the tensile strength. The maximum bonding efficiency and optimal bonding layer were obtained at 8 wt% CeO2. This study expands the applications of solid polymer electrolytes as encapsulation bonding materials.

scholarly journals A System in Package Based on a Piezoelectric Micromachined Ultrasonic Transducer Matrix for Ranging Applications

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2590
Author(s):  
Alexandre Robichaud ◽  
Dominic Deslandes ◽  
Paul-Vahé Cicek ◽  
Frederic Nabki
Keyword(s):  
High Voltage ◽  
Integrated Circuit ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Transimpedance Amplifier ◽  
Measurement Results ◽  
Ultrasonic Ranging ◽  
High Voltage Pulser ◽  
Working Frequency ◽  
Simulation Results

This paper proposes a system in package (SiP) for ultrasonic ranging composed of a 4 × 8 matrix of piezoelectric micromachined ultrasonic transducers (PMUT) and an interface integrated circuit (IC). The PMUT matrix is fabricated using the PiezoMUMPS process and the IC is implemented in the AMS 0.35 µm technology. Simulation results for the PMUT are compared to the measurement results, and an equivalent circuit has been derived to allow a better approximation of the load of the PMUT on the IC. The control circuit is composed of a high-voltage pulser to drive the PMUT for transmission and of a transimpedance amplifier to amplify the received echo. The working frequency of the system is 1.5 MHz.

Design and characteristics of reflectivity tunable mirror with MZI and loop waveguide on SOI

2021 ◽  
Author(s):  
Yutaka Makihara ◽  
Moataz Eissa ◽  
Tomohiro AMEMIYA ◽  
Nobuhiko Nishiyama
Keyword(s):  
Phase Shift ◽  
Coupling Coefficient ◽  
Integrated Circuit ◽  
Silicon Photonics ◽  
Silicon On Insulator ◽  
Zehnder Interferometer ◽  
Directional Couplers ◽  
Photonic Integrated Circuit ◽  
Active Elements ◽  
Measurement Results

Abstract To achieve a reconfigurable photonic integrated circuit with active elements, we proposed a reflectivity tunable mirror constructed using a Mach–Zehnder interferometer (MZI) with a micro heater and loop waveguide on a silicon photonics platform. In this paper, the principle of the operation, design, fabrication, and measurement results of the mirror are presented. In theory, the phase shift dependence of the mirror relies on the coupling coefficient of the directional couplers of the MZI. When the coupling coefficient κ2 was 0.5 and 0.15, the reflection could be turned on and off with a phase shift of π/2 and π, respectively. The reflection power of the fabricated mirror on the silicon on insulator (SOI) substrate was changed by more than 20 dB by a phase shift. In addition, it was demonstrated that the phase shift dependence of the mirror changes with the coupling coefficient of the fabricated devices.

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